Updated

Anti-government protesters stormed a convention center where leaders of Asian nations planned to meet Saturday, smashing doors and searching room by room for the prime minister.

Thailand canceled the summit and airlifted the leaders out by helicopter.

The red-shirted protesters, who are calling for the resignation of Thai Prime Minister Abhisit Vejjajiva, declared victory and walked away from the complex after about an hour.

"We have won. We have stopped them from holding a summit," Jakrapob Penkair, one of the protest leaders, said in the capital, Bangkok. "But we have not achieved our goal yet. We will continue to protest in Bangkok until Abhisit resigns."

Abhisit, who has repeatedly refused to step down, went on national television and declared a state of emergency in the area surrounding the summit, but revoked it about six hours later after the leaders left safely.

He called the protesters "enemies of Thailand."

The chaos is a huge embarrassment for Abhisit, who has been trying to project an image of calm and normality since taking power in a parliamentary vote four months ago after a court dissolved the previous government for election fraud. His ascent to power — the fifth Thai government in a little over two years — came after protests by a rival group of protesters shut down the capital's airports and endangered the country's tourism industry.

The latest demonstrations raise tension in Thailand, where anti-government crowds as big as 100,000 marched in Bangkok this past week, and increased the threat of violence and a possible confrontation between the military and the protesters.

"The situation has gotten completely out of hand. Violence and bloodshed is very much possible," said Charnvit Kasetsiri, a historian and former rector of Bangkok's Thammasat University. "The country is very split and it might have reached the point of no return."

More than 1,000 demonstrators smashed through the convention center's glass doors and ran through the building, overturning tables, blowing horns, waving Thai flags and screaming, "Abhisit get out!"

They are supporters of former Prime Minister Thaksin Shinawatra, who was deposed in a 2006 military coup for alleged corruption and abuse of power. They say Abhisit was not elected by the people and should step down so new elections can be held.

Despite days of mass protests — including an attack on the prime minister's car — the Thai government had promised visiting heads of state that they would be safe from the unrest.

The leaders were evacuated by helicopter from Pattaya to a nearby military airport, said government spokesman Supachai Jaisamuth.

"The meeting cannot go on. We have to consider the security of the leaders," Supachai said. "The situation is too violent and it is a security concern for the leaders."

The protesters met little resistance from a thin line of unarmed soldiers in riot gear who were standing in front of the summit venue. When the protesters rushed toward the building and started pounding on the glass facade, the soldiers attempted to push them back but were overwhelmed by their numbers.

Officials had said that 8,000 police were being deployed for security, but few were seen around the summit venue in Pattaya, about 140 kilometers (90 miles) southeast of Bangkok.

"The government was clear from the beginning that the measures used against demonstrators wouldn't include any arms," said government spokesman Panitan Wattanayagorn. "We have to review the process again to see if these measures are appropriate for the next meeting."

Nine leaders from Southeast Asian nations were in a nearby hotel on the convention grounds at the time the protesters broke in, said Foreign Ministry spokesman Tharit Charungvat. Abhisit said the leaders were "very understanding" about the abrupt cancellation.

It scuttled a chance for the leaders of 16 nations, including China, Japan and South Korea, to confer on ways to combat the global slump that has battered Asia's export-oriented economies. North Korea's recent rocket launch also was to be discussed at the gathering, which on Sunday was to include Australia, New Zealand and India for the full-fledged East Asia Summit.

Government spokesman Panitan Wattanayagorn said he hoped the summit could be rescheduled within the next few months.

The summit started Friday with a dinner among leaders from the 10-member Association of Southeast Asian Nations, but fell apart Saturday as protesters blocked access to some of the delegates' hotels.

Organizers had to delay — and then cancel — morning meetings between the leaders of ASEAN and China, South Korea and Japan.

Japanese Prime Minister Taro Aso, South Korean President Lee Myung-bak and Chinese Premier Wen Jiabao managed to meet and discussed North Korea's recent rocket launch, Aso spokesman Osamu Sakashita said.

The three agreed that a "strong message be issued unanimously at an early date," he said. The U.N. Security Council is trying to break a deadlock over how to respond to North Korea's April 5 launch.